1. Field of the Invention
The present invention relates to an air conditioner for a vehicle that recovers vehicle deceleration energy by storing cold (cooling energy) in a cooling heat exchanger during the period of vehicle deceleration.
2. Description of the Related Art
Conventionally, there is an air conditioner, for a vehicle, in which the temperature of air cooled by an evaporator (a cooling heat exchanger) is detected and a compressor is driven and controlled so that the detected temperature becomes equal to a target cooling temperature, and during the period of vehicle deceleration, the target cooling temperature is reduced to a temperature lower than that before deceleration in order to increase the rate of operation (rate of operation time with respect to total time including rest time) of the compressor and vehicle deceleration energy is recovered by storing cold in the cooling heat exchanger (refer to, for example, Patent document 1 and Patent document 2).
On the other hand, there is another air conditioner for a vehicle, in which a fuel consumption saving effect is achieved by keeping a compressor in a resting state for a predetermined time during the period of vehicle deceleration (refer to, for example, Patent document 3).                [Patent Document 1]        Japanese Unexamined Patent Publication (Kokai) No. 57-44511        [Patent Document 2]        Japanese Unexamined Patent Publication (Kokai) No. 2001-105846        [Patent Document 3]        Japanese Unexamined Patent Publication (Kokai) No. 8-295131        
However, in Patent documents 1 and 2 relating to the air conditioner for a vehicle according to a prior art, which air conditioner is described first above, no method is disclosed for improving the fuel consumption saving effect by effectively utilizing the energy recovered during the period of deceleration (the stored cold heat (cooling energy)) while the feelings of passengers are taken into account.
On the other hand, the object of the air conditioner for a vehicle according to a prior art, which air conditioner is described second above, is also to achieve the fuel consumption saving effect and no control that takes into account the feelings of passengers is disclosed in Patent document 3.
The applicants of the present invention have focused on a control to be performed when stored cold heat is utilized because it seems possible to achieve a more marked fuel consumption saving effect by effectively utilizing the stored cold heat, while the feelings of passengers are taken into account, in an air conditioner for a vehicle that recovers vehicle deceleration energy and stores cold in a cooling heat exchanger.